VANCOUVER — Adventurers are being warned to use caution in the mountains north of Vancouver as a winter storm sweeps through the region, increasing the avalanche risk.

Joe Lammers, a forecaster with Avalanche Canada, says as much as 50 centimetres of snow is expected to fall on mountains in the South Coast by Friday.

Environment Canada has issued snowfall and winter storm warnings for Metro Vancouver, saying a frontal system will bring flurries and freezing rain to the area.

Lammers says the snow and strong winds could create unstable slabs in the mountains, and the avalanche danger rating is likely to climb to the considerable level or even to a high rating in the alpine.

He says anyone venturing into the backcountry should be trained in avalanche safety, know how to recognize dangerous terrain and carry appropriate equipment, including shovels, beacons and probes.

Lammers says even experienced back country users should stick to conservative terrain and lower-angle slopes, and be aware of overhead hazards.

Anyone without proper gear or training should stay within bounds at ski resorts, he added.

“It’s all about choosing terrain that’s appropriate for the conditions,” Lammers says.

Avalanche Canada’s danger ratings for the Sea to Sky region north of Vancouver and the South Coast Inland region to the east are also set to go up to considerable by Friday as wintry weather moves across the province.

Unstable snow in British Columbia’s mountains is known to be deadly.

In April, five hikers crossing an unstable snow ledge in the mountains north of Vancouver fell 500 metres to their deaths. Rescuers said it appears the group stepped out on the ledge and the snow collapsed beneath them.